earticle

영어

The wave energy converting system (WEC) can convert the unstable wave energy into stable electric power. In this paper, the new WEC which is mainly composed of three hydraulic circuits viz, the commutation, decompression and speed regulation circuit. It is controlled by various electronic valves. A series of experimentations were done to investigate its static and dynamic characteristics under the condition of variable load and variable flow rate, and its influence on the grid was analyzed as well. The experimental result shows that when the flow rate of the system which is controlled by the electro-hydraulic proportional flow control valve varies, the accumulator conserves part of the hydraulic energy and consequently the output power decreases. The revolving speed and working pressure show the different change trend in the response to the variation of the flow rate. However, when the load varies, the revolving speed of the hydraulic motor varies marginally. In the case of identical load change, the amplitude of variation is not the same at different revolving speed. Because of adopting the proportional flow control valve, the new WEC can be regarded as a non-differential control system which may cause the oscillation of the active power. To avoid this, this paper suggests using the variable-speed constant-frequency device or electrical governor.